Acceptable voltage discrepancy, Voltage at dash vs. voltage at battery Options

[98101]

I started my car after sitting a few days and noticed the dash voltage meter went up over 15V. In Tech Tips 700 I read that overvoltage could lead to battery acid spills, so I quickly shut it off.

Prior to that, I'd noticed the dash gauge reads lower than I'd like when all the lights are on.

I checked the voltage at the battery under different circumstances and they weren't so extreme in either direction. So now I'm wondering what the acceptable differences would be before you'd start to expect a poor (ground?) connection somewhere?


https://www.youtube.com/watch?v=S6BcQC-cjXo

[Spoke]

Short bursts of 16V on the battery should cause no issues. Long exposure to 16V is not good as it would overheat the battery.

To fully understand what is going on the electrical system and layout must be known. That ammeter should be wired from alternator to cabin to battery as Mike mentioned. If not, it would only measure the draw of the accessories in the car.

Do you have a schematic of how the ammeter is connected?

Also, when you saw the 16V, was it stable or bouncing around?

[porschetub]

Short bursts of 16V on the battery should cause no issues. Long exposure to 16V is not good as it would overheat the battery.

To fully understand what is going on the electrical system and layout must be known. That ammeter should be wired from alternator to cabin to battery as Mike mentioned. If not, it would only measure the draw of the accessories in the car.

Do you have a schematic of how the ammeter is connected?

Also, when you saw the 16V, was it stable or bouncing around?

Interesting reading and thanks to the OP for starting it,I'am connected to the wiring for the centre console for my gauge, I get some odd readings that don't line up with battery output,seems under load it lines up closer but the gauge is always lower than the battery (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif) .
Is the wiring that go's to the centre console not up to it to run a gauge or is it just old wire ? is a direct reading from the battery the only solution.....I can do that if needs be.
Thanks.